1. Field of the Invention
The present invention relates generally to the field of data communication and, more particularly, to connectivity processes for use in communication networks to provide automatic detection of various protocols.
2. Related Art
As the popularity of the Internet continues to grow, more businesses and individuals are making greater use of the many services the Internet provides, for example, e-mail, e-commerce, information searches, and the like. Part of the credit for the rapid growth of the Internet can be attributed to various technological advances that have, for example, increased connection speed, simplified the connection process, etc. Presently, accessing the Internet requires the facilitation of an Internet service provider (“ISP”), which can be defined as an organization that provides its clients access to the Internet. A diverse body of methods, protocols and standards is currently utilized by clients to connect to ISP's. As such, in order to provide its clients with Internet access, an ISP has to be able to detect the many different communication protocols.
An ISP must be able to identify, or detect, the particular connection mode utilized by a client modem attempting to log on to the network. The detection is necessary in order for the client modem to be properly connected at the ISP. More particularly, successful communication between the ISP and the client modem is dependent on the client modem being connected to a central site modem (“CSM”) receiving port at the ISP configured to communicate in the same protocol as the protocol utilized by the client modem. Otherwise, communication fails and the connection may be lost if the client modem is connected instead to a port which does not share the client modem's connection mode.
In one conventional method for determining a client modem's specific connection mode, receiving ports at the CSM are pre-configured as either analog or digital. A port in digital mode can be specifically configured as, for example, V.110, V.120, Personal Handyphone Internet Access Forum Standard (“PIAFS”) or other Integrated Service Digital Network (“ISDN”) protocols known in the art. According to this method, after a port has been configured in a specific mode, it cannot accept other types of incoming calls. Thus, a port configured as V.110, for example, would not be able to communicate with a client modem utilizing the V.120 protocol. Once it has been configured, the port is assigned a specific telephone number, and thereafter, any client modem calling the number assigned to that port is assumed to be attempting to set up a connection under the receiving port's configured mode. Consequently, a connection will not be established if the connection mode at the client side is different than the port's configuration, e.g., if the client is dialing a “wrong number.” Another disadvantage with assigning specific telephone numbers to pre-configured ports is the potential for excessive overhead, since sets of telephone numbers have to be allocated to receiving ports even though not all the ports will be operating all the time. Stated another way, there may be lulls in the utilization of specific modes of connection during which time the telephone numbers committed to the ports configured to communicate in such modes remain idle and are therefore wasted.
Another known method for determining a client modem's specific connection mode relies on the local central office (“CO”) transmitting certain information about a call to the ISP. This conventional approach can be implemented in an ISDN architecture, for example, wherein the CO provides the ISP with an ISDN setup message during call establishment. For example, as part of the setup message, the CO can inform the ISP of the particular number dialed by the client modem as well as the connection's bearer capability, which is an ISDN layer 3 service indication that defines the characteristics of a given call. The ISP can use this information to determine the client modem's connection mode. The ISP can then configure the receiving port as a specified mode suitable for communicating with the client modem, based on the information provided by the CO. This approach, however, is necessarily limited by the capabilities of the network and cannot work properly, for example, if no setup message is available.
An alternative method for determining a client modem's connection mode permits a coarse distinction between only ISDN/High-level Data Link Control (“HDLC”) calls and analog calls. According to this method, the receiving port answers the incoming call in ISDN mode. If continuous HDLC flags are detected within a number of milliseconds of answering the call, the port is configured as 56K ISDN. Otherwise, the port will poll for 64K HDLC flags, and a 64K ISDN connection is established if 64K HDLC flags are detected. If both 56K and 64K speeds fail, i.e. if HDLC flags are not detected for either speed, the port is switched to analog mode. Although this method may be effective for distinguishing between certain digital and analog calls, it lacks the capability to discern different digital protocols and their sub-modes. For example, as is known in the art, V.110 is a non-HDLC rate adaptation protocol which enables end-users with relatively low speed devices to use the 64K ISDN network by supporting intermediate transmission rates, including 8K, 16K and 32K. Further, each of the V.110 intermediate rates can support different line speeds. Other non-HDLC digital protocols, such as PIAFS, which can be 56K or 64K, are also not detected by this conventional method.
Thus, there is an intense need in the art for auto detection systems and methods to differentiate between the various protocols and determine the particular protocol of the calling client modem.